Merge tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - Support for userspace to send requests directly to the on-chip GZIP
   accelerator on Power9.

 - Rework of our lockless page table walking (__find_linux_pte()) to
   make it safe against parallel page table manipulations without
   relying on an IPI for serialisation.

 - A series of fixes & enhancements to make our machine check handling
   more robust.

 - Lots of plumbing to add support for "prefixed" (64-bit) instructions
   on Power10.

 - Support for using huge pages for the linear mapping on 8xx (32-bit).

 - Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound
   driver.

 - Removal of some obsolete 40x platforms and associated cruft.

 - Initial support for booting on Power10.

 - Lots of other small features, cleanups & fixes.

Thanks to: Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan,
Andrey Abramov, Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent
Abali, Cédric Le Goater, Chen Zhou, Christian Zigotzky, Christophe
JAILLET, Christophe Leroy, Dmitry Torokhov, Emmanuel Nicolet, Erhard F.,
Gautham R. Shenoy, Geoff Levand, George Spelvin, Greg Kurz, Gustavo A.
R. Silva, Gustavo Walbon, Haren Myneni, Hari Bathini, Joel Stanley,
Jordan Niethe, Kajol Jain, Kees Cook, Leonardo Bras, Madhavan
Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Michal
Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin,
Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram Pai,
Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher
Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler,
Wolfram Sang, Xiongfeng Wang.

* tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (299 commits)
  powerpc/pseries: Make vio and ibmebus initcalls pseries specific
  cxl: Remove dead Kconfig options
  powerpc: Add POWER10 architected mode
  powerpc/dt_cpu_ftrs: Add MMA feature
  powerpc/dt_cpu_ftrs: Enable Prefixed Instructions
  powerpc/dt_cpu_ftrs: Advertise support for ISA v3.1 if selected
  powerpc: Add support for ISA v3.1
  powerpc: Add new HWCAP bits
  powerpc/64s: Don't set FSCR bits in INIT_THREAD
  powerpc/64s: Save FSCR to init_task.thread.fscr after feature init
  powerpc/64s: Don't let DT CPU features set FSCR_DSCR
  powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()
  powerpc/32s: Fix another build failure with CONFIG_PPC_KUAP_DEBUG
  powerpc/module_64: Use special stub for _mcount() with -mprofile-kernel
  powerpc/module_64: Simplify check for -mprofile-kernel ftrace relocations
  powerpc/module_64: Consolidate ftrace code
  powerpc/32: Disable KASAN with pages bigger than 16k
  powerpc/uaccess: Don't set KUEP by default on book3s/32
  powerpc/uaccess: Don't set KUAP by default on book3s/32
  powerpc/8xx: Reduce time spent in allow_user_access() and friends
  ...

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 360367c579de..1a474f6b1992 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -185,11 +185,41 @@ static inline void mm_context_remove_copro(struct mm_struct *mm)
 			dec_mm_active_cpus(mm);
 	}
 }
+
+/*
+ * vas_windows counter shows number of open windows in the mm
+ * context. During context switch, use this counter to clear the
+ * foreign real address mapping (CP_ABORT) for the thread / process
+ * that intend to use COPY/PASTE. When a process closes all windows,
+ * disable CP_ABORT which is expensive to run.
+ *
+ * For user context, register a copro so that TLBIs are seen by the
+ * nest MMU. mm_context_add/remove_vas_window() are used only for user
+ * space windows.
+ */
+static inline void mm_context_add_vas_window(struct mm_struct *mm)
+{
+	atomic_inc(&mm->context.vas_windows);
+	mm_context_add_copro(mm);
+}
+
+static inline void mm_context_remove_vas_window(struct mm_struct *mm)
+{
+	int v;
+
+	mm_context_remove_copro(mm);
+	v = atomic_dec_if_positive(&mm->context.vas_windows);
+
+	/* Detect imbalance between add and remove */
+	WARN_ON(v < 0);
+}
 #else
 static inline void inc_mm_active_cpus(struct mm_struct *mm) { }
 static inline void dec_mm_active_cpus(struct mm_struct *mm) { }
 static inline void mm_context_add_copro(struct mm_struct *mm) { }
 static inline void mm_context_remove_copro(struct mm_struct *mm) { }
+static inline void mm_context_add_vas_windows(struct mm_struct *mm) { }
+static inline void mm_context_remove_vas_windows(struct mm_struct *mm) { }
 #endif